1. Field of the Invention
The present invention relates to an audio output control device and an audio output control method, and is preferably applied to a digital television set that can display two screens at one time, for example.
2. Description of the Related Art
An existing digital television set has a function called two-screen mode. When a user pushes a two-screen button, the digital television set switches from a normal one-screen mode to the two-screen mode. In this case, generally, on the left side of the digital television set is a main screen, while a sub screen is on the right side.
In the two-screen mode, only when the main screen is selected, the digital television set outputs only the main sound of the main screen via a speaker attached to the digital television set.
And in the digital television set, when a right and left arrows button of a remote controller is operated, the digital television set selects, instead of the left-hand main screen, the right-hand sub screen accordingly.
In this case, even though two screens are being displayed on the digital television set, the digital television set emphasizes the main screen in such a way as if the frame of the main screen is selected by a cursor, for example. Accordingly, the fact that the speaker is outputting the main sound of the main screen is visually understandable.
Accordingly, when a right arrow button of the remote controller is pushed, the digital television set performs a switching process. As a result, the frame of the sub screen is emphasized, and the sub sound of the sub screen is being output through the speaker. The above is a usual two-screen mode audio switching method.
By the way, the digital television set has a headphone mode 1: in headphone mode 1, when a headphone is connected to the digital television set, the digital television set stops the output of the above speaker, and outputs the main or sub sound of the selected main or sub screen through the headphone.
Moreover, the digital television set displays a menu on the selected main or sub screen after a user pushes a menu button of the remote controller. From the menu, a headphone mode 2 can be selected.
However, an audio output pattern (regarding the speaker output and the headphone output) of the digital television set to which the headphone is connected is different from when the headphone is not connected, if the headphone mode 2 is selected from the menu.
In reality, as shown in FIG. 1, when the digital television set switches from State T1, in which the two screens are displayed, to State T2, in which the main screen is selected, after a left arrow button of the remote controller is pushed, the speaker becomes State T3 in which only the main sound of the main screen is being output.
Incidentally, even though a TV program's video image is being displayed on the sub screen, the digital television set does not output the sub sound of the sub screen via the speaker, because the main screen is selected.
Moreover, during State T2 in which the main screen is being selected, the digital television set displays the menu on the main screen if the menu button of the remote controller is pushed by a user, who can then select the headphone mode 1 or 2 from the menu. If the digital television set enters State T4 after the selection of the headphone mode 2, the speaker keeps outputting the main sound, and the digital television set then proceeds to State T5 in which the sub sound of the sub screen is supplied to a headphone terminal.
This means that if the headphone was already connected to the headphone terminal of the digital television set, the sub sound would be immediately output through the headphone.
Moreover, during State T2 in which the main screen is being selected, the digital television set may enter State T6 in which the headphone is connected. This substantially means that the headphone mode 1 is selected. In this case, the digital television set stops the output of the main sound through the speaker, and then enters State T7 in which the main sound is output from the headphone via the headphone terminal.
In this case, in State T7, while watching the video image of the main screen, a user listens to the main sound of the main screen only from the headphone.
Incidentally, during State T6 in which the headphone is connected, if the menu button is pushed, the digital television set displays the menu on the main screen. After the headphone mode 2 is selected from the menu in State T8, the digital television set enters State T9 in which the sub sound of the sub screen is output from the speaker, and the main sound of the main screen continues to be output from the headphone via the headphone terminal.
On the other hand, if the digital television set switches from State T1, in which the two screens are displayed, to State T10, in which a sub screen is selected, after the right arrow button of the remote controller is pushed, the digital television set enters State T11 in which only the sub sound of the sub screen is output from the speaker.
Incidentally, even in this case, the digital television set is displaying the TV program's video image on the main screen. However, the speaker stops the output of the main sound of the main screen, because the sub screen is selected.
Moreover, during State T10 in which the sub screen is being selected, the digital television set displays the menu on the sub screen if the menu button of the remote controller is pushed by a user. If the digital television set enters State T12 after the selection of the headphone mode 2 from the menu, the speaker keeps outputting the sub sound, and the digital television set then proceeds to State T13 in which the main sound of the main screen is supplied to the headphone terminal.
This means that if the headphone was already connected to the headphone terminal of the digital television set, the main sound would be immediately output through the headphone.
Moreover, during State T10 in which the sub screen is being selected, the digital television set may enter State T14 in which the headphone is connected. This substantially means that the headphone mode 1 is selected. In this case, the digital television set stops the output of the sub sound through the speaker, and then enters State T15 in which the sub sound is output from the headphone via the headphone terminal.
In this case, in State T15, while watching the video image of the sub screen, a user listens to the sub sound of the sub screen only from the headphone.
Incidentally, during State T14 in which the headphone is connected, if the menu button is pushed, the digital television set displays the menu on the sub screen. If the headphone mode 2 is selected from the menu in State 16, the digital television set enters State T17 in which the main sound of the main screen is output from the speaker, and the sub sound of the sub screen continues to be output from the headphone.
In this manner, with the main or sub screen being selected, the digital television set stops the output of sound from the speaker after the headphone is connected, and starts to output the sound from the headphone.
On the other hand, if the headphone mode 2 is selected from the menu, the digital television set outputs sounds from both the speaker and the headphone. However, which sound the headphone or the speaker outputs depends on which operation is performed first, i.e. entering the menu or connecting the headphone.
On the other hand, as a video device that can display two screens, the one that outputs sound from either a Lch speaker or a Rch speaker and controls the audio volume balance exists (see Jpn. Pat. Laid-open Publication No. H9-307833).